1. Field of the Invention
This invention relates to apparatus and methods for controlling laboratory equipment. More particularly, the apparatus and methods provide for manual input or control of a process condition, such as a potentially hazardous condition.
2. Background of the Related Art
Laboratory equipment is apparatus that is used for scientific experimentation, research, or testing and is typically considered to be of a size that can be housed within a room or building. While there are enumerable types, designs, styles and models of laboratory equipment, a large portion of laboratory equipment is capable of producing hazardous conditions if the equipment is misused or malfunctions. Consequently, laboratory technicians that operate the equipment must be well trained to operate and maintain the equipment under a variety of conditions and uses. Many equipment designs include built-in safety features that prevent or assist in managing hazardous, harmful or otherwise undesirable conditions.
For many laboratory processes, it is important to prevent hazardous conditions from getting out of control. In other words, the nature of much laboratory equipment or processes, and the materials used in association with the laboratory processes, is that the conditions can be managed within certain limits, but it is necessary to interrupt the normal progress of the process if the conditions go beyond those limits. One way to interrupt the process includes the use of manual controls and on/off switches or valves by a laboratory technician having identified the hazardous condition. However, manual control requires the continuous attention of the technician. A generally more effective way to interrupt the process is through the use of programmable controllers in communication with any of a variety of sensors that convert the magnitude of a given process condition into an electronic signal. By appropriately programming the controller to identify hazardous conditions, it is possible for the controller to continuously monitor for hazardous conditions and interrupt the process as appropriate.
However, despite the additional capabilities provided by programmable controllers, there are typically at least a few process and external conditions that the programmable controller was not designed to observe or consider. Examples of important conditions that the controller may not be equipped to detect include, but are not limited to, status of maintenance work such as the electrical supply to the lab, the status of support equipment such as process gas supplies, fluid leaks, and the like. Therefore, it is important that the technician retain ultimate control over the process, especially while the process is experiencing a hazardous condition.
While technician control of the hazardous condition is optimal for the sake of process control, there may be an overriding personal safety interest causing the technician to evacuate the lab. Therefore, there is a need for a process control system that enables technician control over certain critical process parameters during a hazardous condition without subjecting the technician to the risks of exposure to the hazardous condition. It would be desirable if the process control system could be retrofitted onto a variety of laboratory equipment.
The present invention provides a method for remotely controlling laboratory equipment operated by a controller. The method comprises: providing one or more change of state commands from a remote transmitter, wherein the one or more change of state commands are selected from controller change of state commands, hardware change of state commands, or a combination thereof; receiving the one or more change of state commands at a receiver in electronic communication with the controller and the laboratory equipment; communicating controller change of state commands from the receiver to the controller instructing the controller to execute one or more steps to change the state of the laboratory equipment; and communicating hardware change of state commands from the receiver directly to the laboratory equipment. Optionally, the controller may be selected from a microprocessor, sequencing relays, state machines, programmable logic controller, distributed control system, and combinations thereof. Preferably, the hardware change of state commands are communicated directly to critical components of the laboratory equipment without passing through the controller. For example, the hardware change of state command may be communicated through a holding coil, wherein the holding coil is released upon receiving a hardware change of state command. The method may further comprise executing, using the controller, another step in response to each controller change of state command received by the controller. Exemplary change of state commands are selected from shutdown commands, standby commands, reset commands, and combinations thereof.
The invention also provides a system for remotely controlling laboratory equipment operated by a controller. The system comprises: a handheld remote transmitter capable of transmitting one or more change of state commands; a receiver in electronic communication with the controller and in electronic communication with the laboratory equipment; wherein the receiver directs the one or more change of state commands to the controller to execute a next step in a sequence of steps controlling the laboratory equipment. The one or more change of state commands may be selected from hardware change of state commands and controller change of state commands. The receiver may relay hardware change of state commands directly to the laboratory equipment and relay controller change of state commands to the controller. In one embodiment, the system further comprises a holding coil in electromagnetic communication with one or more control element, such as a valve or switch, that is a part of the laboratory equipment, such that a hardware change of state command relayed to the holding coil releases the holding coil and closes the valve.